Disk-based storage devices such as hard disk drives (HDDs) are used to provide non-volatile data storage in a wide variety of different types of data processing systems. A typical HDD comprises a spindle which holds one or more flat circular storage disks, also referred to as platters. Each storage disk comprises a substrate made from a non-magnetic material, such as aluminum, which is coated with a thin layer of magnetic material. In operation, data is read from and written to the storage disk via a read/write head that is moved precisely across the disk surface by a positioning arm as the disk spins at high speed.
Operating performance measures in conventional HDDs include access time, data transfer time and power consumption. In many conventional arrangements, data is stored randomly across the entire storage disk, and therefore accessing the storage disk to read or write date requires significant movements of the read/write head over large portions of the disk surface, which tends to increase access time, data transfer time and power consumption. There are a number of different software tools available that can re-organize the stored data in order to improve performance, such as defragmentation tools for HDDs. However, such software tools can be costly and inefficient, and generally require user activation, which is undesirable. Also, HDD storage capacity has grown increasingly large (e.g., 500 GB+), and therefore many typical computer installations include a large capacity HDD in which only a small portion of that capacity (e.g., 10% to 20%) is accessed on a regular basis.
Advantageous techniques for providing reduced power consumption in an HDD or other disk-based storage device without substantially detracting from HDD reliability are disclosed in U.S. Pat. No. 7,872,825, entitled “Data Storage Drive with Reduced Power Consumption,” which is commonly assigned herewith and incorporated by reference herein. In one or more such techniques, power consumption is reduced in an HDD by varying the supply voltage provided to circuitry within the HDD in response to changes in data transfer rate as different regions of a storage disk are accessed.
However, despite the considerable advances provided by the techniques disclosed in the above-cited U.S. patent, a need remains for further improvements in reducing access time, reducing power consumption and otherwise enhancing the operating performance of an HDD or other type of disk-based storage device.